UNICEF estimates that by 2010, sub-Saharan Africa will have over 53 million orphaned children. Over 30% of these will be orphaned by AIDS. Two-thirds of double orphans are adolescents, reflecting the coming of age of Africa's children orphaned by the AIDS epidemic. Due to their young age and life circumstances, orphaned and separated children are very vulnerable to economic and sexual exploitation, sexual risk taking behaviour, excessive drug and alcohol use, depression, post-traumatic stress disorder, malnutrition, and tuberculosis. Although orphaned children are not yet recognized by UNAIDS as a high risk population for acquiring HIV, these young people are at an especially heightened risk precisely because of their social and economic vulnerability. Although strengthening the capacity of families and communities to protect and care for orphans is the ideal strategy for mitigating the impact of AIDS on family and community structures, there are numerous indicators that families and communities are overwhelmed by the numbers of orphans requiring care. Thus, the quality of care and support these children receive may be compromised. In addition to various configurations of care provided by extended family, several additional care models are emerging. These include formal and informal foster homes, orphanages, community-based programs, government detention centres, homes and schools run by religious institutions or other non-governmental organizations. The overall goal of this study is to improve the health and well-being of orphaned children. The specific aims of the study are therefore to: A.1. Describe existing models of care for children who are orphaned or separated (i.e. actual or virtual orphaned children) in the Uasin Gishu District of Western Kenya; A.2. Investigate the effect of care environment characteristics on key socioeconomic indicators for orphaned and separated children; and A.3. Measure the effect of care environment characteristics on the physical and mental health of the resident children. PUBLIC HEALTH RELEVANCE: More than two thirds (68%) of all people living with HIV live in sub-Saharan Africa, and more than three quarters (76%) of all AIDS deaths in 2007 occurred in this region. AIDS alone has left approximately 15 million children and adolescents without parents, and half of these are adolescents. These children and adolescents are at extraordinarily high risk of adverse physical, social, and psychological outcomes including HIV-infection. The child's home or care environment is a primary target for interventions and support aimed at reducing their risk, and improving their health and well-being.